Mode identification of high-quality-factor single-defect nanocavities in quantum dot-embedded photonic crystals

Abstract

We investigate the quality (Q) factor and the mode dispersion of single-defect nanocavities based on a triangular-lattice GaAs photonic-crystal (PC) membrane, which contain InAs quantum dots (QDs) as a broadband emitter. To obtain a high Q factor for the dipole mode, we modulate the radii and positions of the air holes surrounding the nanocavity while keeping six-fold symmetry. A maximum Q of 17 000 is experimentally demonstrated with a mode volume of V = 0.39(λ/n) 3 . We obtain a Q/V of 44 000(n/λ) 3 , one of the highest values ever reported with QD-embedded PC nanocavities. We also observe ten cavity modes within the first photonic bandgap for the modulated structure. Their dispersion and polarization properties agree well with the numerical results.

Scanning near-field optical microscopy of quantum dots in photonic crystal cavities

“…It shows three distinct peaks between 1320nm and 1330nm. We attribute the two peaks marked with M1 and M2 to dipole modes of the H1 cavity [4]. We attribute the third one to an excitonic emission of a QD, as will be shown later.…”

“…Figures 5 and 6 show the cavity modes M1 and M2. M2 shows a distinct spatial pattern which resembles a dipole mode [4]. On the other hand, M1 has only one lobe.…”

Nanophotonic Quantum Interface for a Single Solid-state Spin

“…However, all of these methods require the cavity to support two degenerate polarization modes, and the quantum dot spin states to be degenerate. Although cavities with degenerate polarization modes can be designed theoretically [97], the degeneracy is usually broken in real devices due to fabrication imperfections, and complex steps are usually required to restore the cavity mode degeneracy [98][99][100]. More importantly, all-optical coherent control typically requires a strong in-plane magnetic field to break the selection rules [21][22][23][24][25][26], which also breaks the degeneracy of the spin transitions.…”

H1 photonic crystal cavities for hybrid quantum information protocols

“…Historically, PhC cavities are not designed for good mode-matching; however, far-field optimization of PhC devices has been recently an active area of research [18][19][20][21][22][23]. In particular, the H1 defect [24], formed by removing one hole from a triangular lattice of air holes, is a promising candidate for the applications described because of its orthogonally-polarized, spectrally-degenerate dipole modes. Although fabrication imperfections lift the degeneracy of the two dipole modes, some post-fabrication techniques have been implemented to restore the degeneracy [25,26].…”